The present invention relates to a vehicle door in which at least one of a door outer panel and a door inner panel constituting a door main body is made of a light alloy.
Further, the present invention relates to a vehicle door structure and, in particular, to a vehicle door structure including an inner panel including a casting and a guard beam which, when a door is closed, extends in the back-and-forth direction of a vehicle and has two end portions thereof respectively fixed to the inner panel.
Further, the present invention relates to an apparatus for preventing a door from intruding into a vehicle room in a vehicle which is collided side-on.
Further, the present invention relates to an inner panel for a vehicle door.
Conventionally, in order to improve the mileage of the vehicle through reduction of the weight thereof, there is known a vehicle door in which a door outer panel includes an expanded material formed of a light alloy such as an aluminum alloy or a magnesium alloy and a door inner panel is made of a casting formed of a light alloy, thereby reducing the weight of the vehicle door (For example, the patent reference 1).
[Patent Reference 1]
JP-A-7-81407
In case where the door outer panel and door inner panel are made of a light alloy in the above-mentioned manner, the mileage of the vehicle can be improved through the reduction of the weight thereof; however, the moment of inertia with a door hinge as a fulcrum is lowered so that, when the door is opened and closed, especially when the door is closed, the operation efficiency (the closing performance) is degraded. That is, to obtain the kinetic energy that is necessary to close the door completely, it is necessary to increase the closing speed of the door.
By the way, in the vehicle door, there are disposed a plurality of built-in parts which are stored within the door main body in such a manner that they are mounted on the door inner panel, such as a window regulator, a door lock, a guard beam and a speaker.
Further, conventionally, as a door structure of this type, there is known a door structure a guard beam is fastened through a bolt joint to a bracket portion cast integrally with an inner panel. In this door structure, the bracket continuously connected portion of the inner panel is formed large in thickness (for example, see the patent reference 2).
[Patent Reference 2]
JP-A-2001-246935
However, in the case of the above structure, there is a fear that, when an impact load is applied to the guard beam due to a side-on collision, stresses can concentrate onto the bracket continuously connected portion of the inner panel and thus a crack can be developed in the inner panel starting in and from the neighboring portion of the bracket continuously connected portion; and, in case where such crack occurs, the impact load cannot be absorbed sufficiently.
Further, conventionally, as an apparatus of this type, there is known an apparatus which, when a vehicle is collided side on, in order to prevent a door from intruding into a vehicle room by bringing a projecting portion formed in the door into engagement with an engaging portion formed in a vehicle body, a reinforcing plate is fixed to the steel-plate-made inner panel of the door and the base end of a pin-shaped member serving as the protecting portion is welded to the reinforcing plate (for example, see the patent reference 3).
[Patent Reference 3]
JP-UM-B-58-19923
However, in the above-cited conventional apparatus, because there are necessary a large number of man-hours and special parts for forming the projecting portion, the cost of the apparatus is high.
Further, conventionally, as an inner panel of this type, there is known an inner panel which is made of a casting (For example, see the patent reference 1).
The belt-shaped area of inner panel extends in the back-and-forth direction of the vehicle so as to cooperate together with an outer panel in forming an entrance for a windowpane and its neighboring portion is required to have high rigidity. However, in the case of the conventional inner panel, there is not found such a device as to be able to meet the above requirement for the rigidity of the belt-shaped area.